San Francisco's plan to provide citywide wireless Internet access, which foundered last summer when EarthLink pulled out, is being revived by a Mountain View company that wants to turn the city into a test site for its vision of a low-cost, community-powered system.

For what would be the country's largest so-called mesh network, a system that uses a constellation of "repeater antennas" to spread signals, Meraki says it will donate enough equipment and Internet access to provide free wireless service to all residents. The network would use as many as 15,000 wireless antennas to relay signals from home to home in a type of digital daisy-chain.

San Francisco is the only city offered free service from Meraki, which plans to use the city as a showroom of sorts to sell its products to other municipalities and communities around the world.

Whether the plan works will be up to residents, who the company hopes will volunteer to erect thousands of devices on their rooftops, balconies or in windows.

Since the venture will use private property, it does not require city approval. Instead, Meraki is betting on San Franciscans' innovative spirit.

"There is no network like this," said Sanjit Biswas, chief executive and co-founder of Meraki.

Meraki, through an initiative called Free the Net, has been testing its mesh system in San Francisco's Mission, Lower Haight and Alamo Square neighborhoods since the spring. About 500 repeaters already are in use, providing service to 40,000 users.

With the backing of venture capital firms Sequoia Capital, DAG Ventures and Northgate Capital, which have contributed $20 million, Meraki plans to blanket the city for less than $5 million, compared to the estimated $14 million to $17 million EarthLink had estimated it would cost to build a city network.

Meraki officials said they expect every neighborhood to get some access by the end of this year.

Meraki said it will deliver download speeds of 1 megabit per second, which is three times as fast as the speed for free access proposed in the city's original plan. The company will not gather private user data, Biswas added.

Security will be similar to that of Internet hot spots - that is, not infallible - so users should be careful about using the system for sensitive transactions, the company said.

The Meraki network won't be required to be as reliable as EarthLink's was supposed to be because the company has no large-scale agreement with the city. But it still could help the city reach its goal of bridging the so-called digital divide.

Nathan Ballard, spokesman for Mayor Gavin Newsom, said the city has been working with companies like Meraki, FON and SFLan to help build out wireless projects to reach the most needy. The city already is using some of the technology in housing authority properties and is looking at expanding those efforts to other low-income areas, he said.

"We are working with these entities to explore how the city can support and partner with these efforts - helping publicize and grow the network without the bureaucracy and politics that challenged our last effort to bring free Wi-Fi to San Francisco," he said.

Aaron Peskin, president of the Board of Supervisors, said he wanted to hear more details about the system but was intrigued by the premise.

"It sounds like it might fill some of our needs," Peskin said.

The key to Meraki's model is that it doesn't require a lot of expensive antennas. The repeater antennas that form the largest part of the network sell for $49. Their signals connect to larger outdoor antennas that sell for $99. Together, they can deliver Internet access using a minimal number of Internet connections.

The San Francisco network, for example, can feature one DSL line that supports anywhere from 10 to 50 repeaters. With the mesh structure, Meraki also can reroute traffic to avoid any malfunctioning antennas. This gives the network stability and reach at a low cost. With the San Francisco project, Meraki also will pay for the Internet access so users won't be asked to share their personal Internet connection.

That differentiates Meraki's network from FON, a Spanish company that has given away a number of free routers in San Francisco in an attempt to create a similar community-based network.

Esme Vos, founder of MuniWireless.com, a group that tracks municipal Wi-Fi projects, said the FON network hasn't really taken off, in part because users are asked to share their network connection. But, she said, Meraki faces the same challenges in getting users to install new equipment.

"That's why these wireless operators like to deal with one partner. You just put up antennas on city light poles and you're done," Vos said. "Here you have to deal with individual owners."

Vos also questioned whether the system will be able to deliver enough bandwidth when it grows to serve the entire city.

Biswas said the network still will be able to deliver high speeds because of the way it's configured.

After a tough year for municipal wireless in which projects in San Francisco, Houston and Chicago were canceled or postponed, cities have been looking for alternatives, said wireless consultant Craig Settles of Oakland. The Meraki example in San Francisco could inspire communities to look at such a low-cost approach in lieu of larger, more expensive networks, he said.

"What Meraki offers cities is a lower cost and a low resource-intensive approach," Settles said. "This allows a city to achieve a noble goal with the economic realities of the day."

Free the Net

Meraki wants to build a free wireless network to eventually cover all of San Francisco - provided residents agree to install antennas on their property. To sign up, go to sf.meraki.com.